There is conventionally known a repeater that extracts, when receiving a frame, the transmission destination address of the frame, retrieves a port to which a terminal corresponding to the transmission destination address is connected, and repeats the frame via the retrieved port.
For example, Japanese Laid-open Patent Publication No. 2005-303410 and Japanese Laid-open Patent Publication No. 2006-129036 disclose a technology for providing a learning table that registers, each time a frame is received, the transmission source address of the frame in association with a reception port, retrieving an address identical with the transmission destination address of the reception frame from the learning table, and repeating the frame via a port corresponding to the retrieved address.
However, the conventional technology has a problem in that communication efficiency of a network is degraded because a transmission source address is overwritten on an address stored in the learning table to be registered in the learning table regardless of frequency by which the address stored in the learning table is identical with the transmission destination address of the reception frame.
In other words, in the conventional technology, when a transmission source address is overwritten on an address stored in the learning table to be registered in the learning table, the transmission source address is overwritten on an address of which the registration lapse time is the longest among addresses registered in association with a port number of a port identical with the reception port. The registration lapse time is a time for which an address is held in the learning table after the address is last registered in the learning table.
Therefore, in the conventional technology, an address that is identical with a transmission destination address of a reception frame at high frequency can be overwritten by a transmission source address of a newly received frame and be deleted from the learning table only because the registration lapse time of the address is the longest.
As a result, the conventional technology has a problem in that communication efficiency of a network is degraded because traffic is excessively increased by frequently performing a process (hereinafter, flooding process) of copying and repeating a frame through all ports other than a port that receives the frame. The flooding process is a process of repeating a frame when an address identical with a transmission destination address is not registered in the learning table.